The present invention relates to a cosmetic comprising hydrofluoroether (abbreviated hereinafter into xe2x80x9cHFExe2x80x9d) having a viscosity of less than 5 mPaxc2x7s at 25xc2x0 C. which is a fluorine-containing solvent causing no environmental disruption and being highly safe for the skin. The HFE is characterized by these properties as well as by high solubility in fluorine-containing oil having a viscosity of at least 5 mPaxc2x7s at 25xc2x0 C. and high dispersibility in a fluorine compound-treated powder.
In recent years, cosmetics incorporating volatile solvents such as isoparaffin and cyclic silicone are frequently used. These volatile solvents have the advantage that upon application there is a refreshing feeling and their solubility is high, and their use can easily improve the feeling of cosmetics in use and increase the functionality thereof. However, isoparaffin and cyclic silicone severely irritate the skin and have the problem of their adverse influence on the environment after volatilization.
Fluorocarbons such as perfluorohexane, chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) have also been examined as substitutes for these solvents. Because the ozone depletion coefficient and warming coefficient of these solvents are high, there is the disadvantage that they are highly dangerous owing to environmental disruption.
As a result of the intense study for solving the problem described above, the present inventors found that a partially fluorinated fluorine-containing solvent, the HFE, is highly safe for the skin and has less or no influence on the environment. In addition to the properties described above, the HFE has high solubility in a fluorine-containing oil used frequently in recent cosmetics and high dispersibility in fluorine compound-treated powders, thus easily permitting improvements in the feeling of cosmetics upon use, and giving a high functionality.
The present invention provides a cosmetic comprising at least 1% by weight of the HFE having a viscosity of less than 5 mPaxc2x7s at 25xc2x0 C., represented by the general formula (1):
CnHmF1xe2x80x94Oxe2x80x94CxHyFzxe2x80x83xe2x80x83(1)
wherein n is a number of 1 to 12, m is a number of 0 to 25, 1 is a number of 0 to 11, m+1=2n=2x+1, x is a number of 1 to 12, y is a number of 0 to 25, z is a number of 0 to 11, and y+z=2x+1, provided that m and y are not be simultaneously zero, and 1 and z are not be simultaneously zero.
The cosmetic of the present invention serve as a finishing cosmetic such as foundation, face powder, cheek color and eye color, a fundamental cosmetic such as face lotion, milky lotion, cream and sunscreen milky lotion, and hair-caring products such as rinse and conditioner, and lipstick overcoat.
Preferably, the HFE is of the general formula (1xe2x80x2):
CnF2n+1xe2x80x94Oxe2x80x94CxH2x+1xe2x80x83xe2x80x83(1xe2x80x2)
wherein n is a number of 1 to 12, and x is a number of 1 to 12.
In the formulas (1) and (1xe2x80x2), n may be e.g. 1 to 10, particularly 1 to 6, and x may be e.g. 1 to 10, particularly 1 to 6.
Specific examples of the HFE include:
C4F9OCH3, C4F9OC2H5, C4F9OC3H7, C5F11OC2H5, C3F7OC4H9 and C4F9OC4H9.
The HFE may be incorporated alone into the cosmetic or may be used as a mixture of at least two types. The amount of the HFE is at least 1% by weight, for example 1 to 99.9% by weight, preferably 5 to 99% by weight, particularly 10 to 99% by weight, based on the cosmetic. The cosmetic comprising the HFE can be produced in a conventional manner.
The HFE is advantageously superior in the ability to dissolve a fluorine-containing oil having a viscosity of at least 5 mPaxc2x7s at 25xc2x0 C. By virtue of this advantage, the cosmetic having the advantage never achieved can be produced. It is preferable that at least 1% by weight of the fluorine-containing oil and at least 5% by weight of the HFE are contained in the cosmetic. For example, the amount of the fluorine-containing oil is preferably 1 to 90% by weight, particularly 5 to 50% by weight, for example 5 to 20% by weight, based on the cosmetic. For example, a weight ratio of the fluorine-containing oil to the HFE may be in the range of from 1:100 to 1:5, preferably from 1:90 to 1:10.
The fluorine-containing oil having a viscosity of at least 5 mPaxc2x7s may be, for example, a perfluoropolyether, or a fluorine-based oil represented by the general formula (2): 
wherein R1a and R1d are each a hydrogen atom or a partially or completely fluorinated aliphatic group having 1 to 20 carbon atoms; R1b and R1c are each a hydrogen atom, or an aliphatic group having 1 to 20 carbon atoms, or a partially or completely fluorinated aliphatic group having 1 to 20 carbon atoms, with the proviso that at least one of R1a to R1d is a partially or completely fluorinated aliphatic group having 1 to 20 carbon atoms; and n is a number of 1 to 20, or a fluorine-based oil represented by the general formula (3): 
wherein R2a is a hydrogen atom or a partially or completely fluorinated aliphatic group having 1 to 20 carbon atoms; R2b, R2c and R2d are each an aliphatic group having 1 to 20 carbon atoms or a partially or completely fluorinated aliphatic group having 1 to 20 carbon atoms, with the proviso that at least one of R2a to R2d is a partially or completely fluorinated aliphatic group having 1 to 20 carbon atoms; and m is a number of 1 to 20.
The viscosity of the fluorine-containing oil is e.g. at least 5 mPaxc2x7s, particularly 10 to 10,000 mPaxc2x7s. The viscosity of the fluorine oil (and the HFE) was measured by a Brookfield type viscometer or a capillary tube viscometer.
Specific examples of the perfluoropolyether include:
F(CF(CF3)CF2O)nCF2CF3 (KRYTOX manufactured by Du Pont Co.);
CF3O(CF(CF3)CF2O)n(CF2O)mCF3 (FOMBLIN Y manufactured by Montefluos Ltd.);
CF3O(CF2CF2O)n(CF2I)mCF3 (FOMBLIN Z manufactured by Montefluos Ltd.); and
F(CF2CF2CF2O)nCF2CF3 (DEMNUM manufactured by Daikin Industries, Ltd.).
A number average molecular weight of the perfluoropolyether (as determined by 19F-NMR) is preferably in the range of 1,000 to 10,000.
In the general formulas (2) and (3), if R1a, R1b, R1c, R1d, R2a, R2b, R2c and R2d are partially or fully fluorinated aliphatic groups, these may contain an oxygen atom or an unsaturated bond. The partially fluorinated aliphatic group may be e.g. R10OCH2 group (R10 is a partially or fully fluorinated aliphatic group (e.g. alkyl group)). Examples of the partially or fully fluorinated aliphatic group are as follows: 
If R1b, R1c, R2b, R2c and R2d are a C1 to C20 aliphatic group, these may have an oxygen atom. Examples of the C1 to C20 aliphatic group include an alkyl group such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and t-butyl as well as a hydroxyalkyl group such as hydroxymethyl and 2-hydroxyethyl (xe2x80x94CH2CH2OH).
R1b, R1c, R2b and R2c in the repeating unit may be the same or different.
The number of carbon atoms in each of R1a to R1d and R2a to R2d is from 1 to 10, particularly from 2 to 4.
Specific examples of the fluorine-based oil represented by the general formula (2) are as follows: 
Specific examples of the fluorine-based oil represented by the general formula (3) are as follows: 
The fluorine-containing oil may be a mixture of at least two types. For example, a mixture consisting of the fluorine-based oils of the general formulas (2) and (3) at a weight ratio of from 5:95 to 95:5, for example 20:80 to 80:20, may be used as the fluorine-containing oil.
The HFE of the present invention is advantageously superior in the ability to disperse a fluorine compound-treated powder. By use of this advantage, the cosmetic having the characteristics never achieved in the past can be produced as well.
It is preferable that at least 1% by weight, based on the cosmetic, of the fluorine compound-treated powder and at least 5% by weight, based on the cosmetic, of the HFE are contained. For example, the amount of the fluorine compound-treated powder in the cosmetic is preferably 1 to 90% by weight, particularly 5 to 50% by weight, for example 5 to 20% by weight, based on the cosmetic. For example, the weight ratio of the fluorine compound-treated powder to the HFE may be in the range of from 1:100 to 1:5, preferably 1:90 to 1:10.
The fluorine compound-treated powder may be a powder which is surface-treated with a fluorine-containing phosphate ester represented, for example, by the general formula (4):
[Rfxe2x80x94Axe2x80x94O]nPO(OM)3xe2x88x92nxe2x80x83xe2x80x83(4)
wherein Rf represents a C6 to C16 polyfluoroalkyl group or perfluoropolyether group,
xe2x80x9cAxe2x80x9d represents a C1 to C4 alkylene group, 
(wherein R1 is a C1 to C4 alkyl group and R2 is a C1 to C4 alkylene group), or 
wherein xe2x80x9cMxe2x80x9d represents a hydrogen atom, a metal atom, ammonium or substituted ammonium, and n is a number of 1 to 3.
A base powder to be treated includes inorganic powder such as talc, kaolin, mica, mica titanium, titanium oxide, iron oxide, magnesium oxide, zinc monoxide, zinc dioxide, heavy or light calcium carbonate, dibasic calcium phosphate, aluminum hydroxide, barium sulfate, silica, alumina, silica gel, carbon black, antimony oxide, magnesium silicate aluminate and magnesium metasilicate aluminate, as well as an organic powder such as protein powder, fish scale, metallic soap, polyvinyl chloride, nylon-12, microcrystalline fiber powder and tar pigment.
The base powder may be treated with 1 to 10% by weight, relative to the base powder, of the fluorine-containing phosphate ester. The surface treatment may be generally surface coating.
In the present invention, suitable chemicals for modifying the feeling in use may be also employed in the step of surface treatment. Examples of the chemicals for modifying the feeling of the cosmetic powder in use include lecithin, N-mono long-chain acyl basic amino acids, silicone, chitosan, collagen and wax.
When the fluorine compound-treated powder is incorporated into the cosmetic, at least two types of the powders may be mixed.
Furthermore, the cosmetic may simultaneously comprise three ingredients, that is, HFE, the fluorine-containing oil and the fluorine compound-treated powder. Based on the cosmetic comprising three ingredients, the HFE may be contained in an amount of 5 to 99% by weight, preferably 10 to 90% by weight, the fluorine-containing oil may be contained in an amount of 0.5 to 90% by weight, preferably 5 to 50% by weight, and the fluorine compound-treated powder may be contained in an amount of 0.5 to 90% by weight, preferably 5 to 50% by weight.
The cosmetic of the present invention may contain solid or semi-solid oils such as Vaseline, lanolin, ceresin, microcrystalline wax, carnauba wax, candelilla wax, higher aliphatic acids and higher alcohols; liquid oils such as squalane, liquid paraffin, ester oils, diglycerides, triglycerides and silicone oil; fluorine-containing oils such as perfluoropolyether, perfluorodecalin and perfluoroctane; water- and oil-soluble polymers, surface active agents, coloring agents such as organic dyestuffs, ethanol, preservatives, antioxidants, pigments, thickening agents, pH adjusters, perfumes, UV absorbers, humectants, blood stream promoters, coolants, sweat regulators, germicides, skin activators etc.
The examples of the present invention is described specifically, but this description does not limit the present invention.